Post 47 –by Gautam Shah (Lecture series: Space Perception’ -Article-II of 15).
One of the most important functions of architectural openings is the composition of vision. And the fascinating aspect of the visual makeup, inward or outward, is the stratification of the view. The stratification is circumstantial, intentional or accidental.
The view of outside or inside gains different dimension depending on how far or close, one is from the picture plane (face of the opening), what is covered within the nominal cone of vision, and the postural-gestural movements of the head and body to scan the view. Architectonic elements also mask, frame and filter the view.
Regular architectural openings, and incidental ones like the crevices or holes, are effective when the surfaces like wall or roof are very extensive. Openings arouse curiosity to discover the realm on the other side. Windows, can be enlarged or reduced in size to regulate the scope of vision, but doors cannot be modified due to the basic anthropometric requirements. For visual makeup openings are transgressed outward and inward, through the floor or roof.
The mechanics of vision depend on several factors, such as: a vision cones, extent of the framing element, sill and lintel level, shading devices, depth of opening, design or configuration, quality of glazing, level of maintenance, differences of illumination between outside and inside, amount of the glare, treatments on internal and external faces of openings, quality of external surroundings, internal reflections, tasks, orientation, climatic conditions, illumination conditions, need for protection and privacy, etc.
The visual makeup also depends on the position of the viewer.
● Visual scope and depth of openings: A viewer deep inside, away from the opening, gets a nominal straight or horizontal view. But as one comes closer, the scope of vision increases. The visual makeup is surmounted by architectural elements like overhangs, horizontal fins, the sill height, height of the opening in comparison to eye level (in supine-sitting-or standing position) and depth of opening.
● Visual scope for clerestory openings: For a person positioned close to the plane of opening, if the sill level is above eye level, the range of visual scope is small. This scope becomes larger as one moves away from the plane of opening.
● Visual scope and the datum of floor: Tall buildings (multi-storeyed) have several floors, each of which offers different vistas. For a person positioned, approximately as deep as the internal height of the floor, the visual-scape is nearly horizontal. So at lower floor one sees street and surrounding activities, from mid floors the view consists of horizon consisting of tree or building tops, but on upper floors the view is of the horizon. In the second and third categories, at night additional flickering brightness from bottom up sources is very distractive, such as from the head light beams of moving vehicles, street lights, road-light signals, illumination or glow from hoardings and neighbouring buildings. These reflections fall on the ceilings and sometimes on the wall, but distort the interior visual effects.
● Surrounds of the openings, all four sides, jambs, sills, or bottom of the door-heads, alter the inward and outward vision scope. The sloped surfaces due to chamferring on the outward or inward faces, enlarged the perceptive size of the opening. It however made the perception depth ambiguous due to the foreshortening.
● The dividers or sub elements of openings, such as traceries, mullions, muntins, are primarily used as mid support in the frame or sash, and divide the glazing into smaller units. Early age glazing units were small but had fuzzy transparency and wavy patterns of making. These crude smaller units, however divided the view and made it bearable.
● Openings in moving vehicles offer dynamic scenery, where the objects could be both, stationary as well as moving. Uniformly shaped and sized objects, in nearby visual range seem more dynamic, but variegated objects in distance, seem to be less moving. These two fields when viewed through separated horizontal sections of an opening, pose distinctly different scenes. Such experiences are more common in carriages with additional windows at higher level.
● Stratification is very important issue with openings of fixed glazing and shop front windows, both of which serve the function of a picture window that frames a scene or to displayed items.
● Fixed glazing windows show a scene consisting of several layers depending on the point of observation and floor datum. These layers, typically at lower section consist of ground level shrubs and movement of people and vehicles. At mid level the scene consists of mid-portion of trees (effects of breeze-wind) and perhaps deeper vista. At higher level, (the top lite) mainly sky and upper sections of very tall buildings (becoming impersonal due to greater inclination-distance) are seen. Of the three, the change is more pronounced at the lower section, and often curtained of with ‘parlour curtains’.
Shop front windows reflect the opposite side scene, in mainly two distinct strata. Upper part, if shadowed by solar inclination or overhang, has little reflection, but lower section has strong reflection (called ‘bounce-back’). Reflections at lower section do not allow view inside, unless interior portions have additional illumination.
This is the II article (of intended 15) in series ‘Space Perception’ that will form a course of One semester.